android: add qmake based build for Subsurface-mobile

Several features that are needed to create Android bundles with the
current NDK and QT 5.15 aren't easily available when using cmake. Given
that we already do a qmake based build for iOS, I decided to simply
switch Android to that as well.

An added complication is that some of the magic that qmake uses to do
the right things fails if the .pro file isn't in the root directory of
your project. So this is right now somewhat inconsistent with the way we
build for iOS. Something that should get cleaned up in the near future
as it makes no sense to maintain two separate .pro files.

This commits also adds a new build shell script to drive the assembly of
all the dependencies. Once again this is a new file with the old one
left in place for now (but to be removed fairly soon).

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

packaging/android/build.sh

@@ -1,4 +1,10 @@
 #!/bin/bash
+#
+# THIS IS OBSOLETE AN ONLY WORKS UP TO Qt 5.13
+# for now keeping it around for reference
+
+
+
 #
 # Filesystem layout considerations...
 # for this explanation I assume that your Subsurface sources are in